Hull and Stability

3.15 Type A and Type B ships
3.15.1 Type A ship
A Type A ship is one which:
is designed to carry only liquid cargoes in bulk;
has a high integrity of the exposed deck with only small
access openings to cargo compartments, closed by
watertight gasketed covers of steel or equivalent material;
and
has low permeability of loaded cargo compartments.
A Type A ship is to be assigned a freeboard following the
requirements reported in the International Load Line Convention
1966, as amended.
3.15.2 Type B ship
All ships which do not come within the provisions regarding
Type A ships stated in [3.15.1] are to be considered as Type
B ships.
A Type B ship is to be assigned a freeboard following the
requirements reported in the International Load Line Convention
1966, as amended.
3.15.3 Type B-60 ship
A Type B-60 ship is any Type B ship of over 100 metres in
length which, fulfilling the requirements reported in Regulation
27 of Part 3, Annex I, Chapter III of the International
Convention on Load Lines, 1966 and Protocol of 1988, as
amended, is assigned with a value of tabular freeboard
which can be reduced up to 60 per cent of the difference
between the “B” and “A” tabular values for the appropriate
ship lengths.
3.15.4 Type B-100 ships
A Type B-100 ship is any Type B ship of over 100 metres in
length which, fulfilling the requirements reported in Regulation
27 of Part 3, Annex I, Chapter III of the International
Convention on Load Lines, 1966 and Protocol of 1988, as
amended, is assigned with a value of tabular freeboard
which can be reduced up to 100 per cent of the difference
between the “B” and “A” tabular values for the appropriate
ship lengths.
3.16 Positions 1 and 2
3.16.1 Position 1
Position 1 includes:
exposed freeboard and raised quarter decks,
exposed superstructure decks situated forward of 0,25
L LL from the perpendicular, at the forward side of the
stem, to the waterline at 85% of the least moulded
depth measured from the top of the keel.
3.16.2 Position 2 (1/1/2005)
Pt B, Ch 1, Sec 2
Position 2 includes:
exposed superstructure decks situated aft of 0,25 L from
the perpendicular, at the forward side of the stem, to the
waterline at 85% of the least moulded depth measured
from the top of the keel and located at least one standard
height of superstructure above the freeboard deck,
exposed superstructure decks situated forward of 0,25 L
from the perpendicular, at the forward side of the stem,
to the waterline at 85% of the least moulded depth
measured from the top of the keel and located at least
two standard heights of superstructure above the freeboard
deck.
4 Reference co-ordinate system
RINA Rules 2012 21
4.1
4.1.1 The ship’s geometry, motions, accelerations and
loads are defined with respect to the following right-hand
co-ordinate system (see Fig 2):
Origin: at the intersection among the longitudinal plane
of symmetry of ship, the aft end of L and the baseline
X axis: longitudinal axis, positive forwards
Y axis: transverse axis, positive towards portside
Z axis: vertical axis, positive upwards.
4.1.2 Positive rotations are oriented in anti-clockwise
direction about the X, Y and Z axes.
Y
Figure 2 : Reference co-ordinate system
Z
AE
X